Articles de revista
http://hdl.handle.net/2117/658
Sun, 11 Dec 2016 02:52:44 GMT
20161211T02:52:44Z

Low cost transmission line demonstrator for a novel intermediate level communication engineering laboratory
http://hdl.handle.net/2117/97952
Low cost transmission line demonstrator for a novel intermediate level communication engineering laboratory
Torres Torres, Francisco; Corbella Sanahuja, Ignasi; Cardama Aznar, Ángel; Romeu Robert, Jordi; Galíndez, O
This paper is devoted to the description of a transmission line laboratory demonstrator for intermediate level communication engineering students, within a course on radiation and guided waves. Student activities have been organized according to the needs of intermediate level students and the objectives of an introductory laboratory, which are substantially different from those of specialized laboratory activities aimed at higher level students and placed just before graduation. Since a large number of students attend these laboratory sessions before they choose their specialty, low cost is an unavoidable requirement to be considered. For this reason, the measurement setup makes use of standard instrumentation, usually available in a basic electronic laboratory, which allows multiplication of work places at a reasonable cost. Both time domain reflectometry and sinusoidal steady state measurements are presented to characterize the main parameters of a coaxial line. However, discussions are mainly focused on sinusoidal measurements, which are scarce in the literature and exclusively devoted to slotted line measurements. The experimental work undertaken by the students gives them insight into main transmission line parameter and features: line impedance, propagation speed, its behavior as an impedance transformer, the complex nature of the measured magnitudes and the standing wave behavior of voltage and attenuation.
Fri, 09 Dec 2016 15:23:33 GMT
http://hdl.handle.net/2117/97952
20161209T15:23:33Z
Torres Torres, Francisco
Corbella Sanahuja, Ignasi
Cardama Aznar, Ángel
Romeu Robert, Jordi
Galíndez, O
This paper is devoted to the description of a transmission line laboratory demonstrator for intermediate level communication engineering students, within a course on radiation and guided waves. Student activities have been organized according to the needs of intermediate level students and the objectives of an introductory laboratory, which are substantially different from those of specialized laboratory activities aimed at higher level students and placed just before graduation. Since a large number of students attend these laboratory sessions before they choose their specialty, low cost is an unavoidable requirement to be considered. For this reason, the measurement setup makes use of standard instrumentation, usually available in a basic electronic laboratory, which allows multiplication of work places at a reasonable cost. Both time domain reflectometry and sinusoidal steady state measurements are presented to characterize the main parameters of a coaxial line. However, discussions are mainly focused on sinusoidal measurements, which are scarce in the literature and exclusively devoted to slotted line measurements. The experimental work undertaken by the students gives them insight into main transmission line parameter and features: line impedance, propagation speed, its behavior as an impedance transformer, the complex nature of the measured magnitudes and the standing wave behavior of voltage and attenuation.

Integral equation mei applied to threedimensional arbitrary surfaces
http://hdl.handle.net/2117/97898
Integral equation mei applied to threedimensional arbitrary surfaces
Rius Casals, Juan Manuel; Parrón Granados, Josep; Úbeda Farré, Eduard; Mosig, J R
The authors present a new formulation of the integral equation of the measured equation of invariance (MEI) as a confined field integral equation discretised by the method of moments, in which the use of numerically derived testing functions results in an approximately sparse linear system with storage memory requirements and a CPU time for computing the matrix coefficients proportional to the number of unknowns.
Wed, 07 Dec 2016 16:46:43 GMT
http://hdl.handle.net/2117/97898
20161207T16:46:43Z
Rius Casals, Juan Manuel
Parrón Granados, Josep
Úbeda Farré, Eduard
Mosig, J R
The authors present a new formulation of the integral equation of the measured equation of invariance (MEI) as a confined field integral equation discretised by the method of moments, in which the use of numerically derived testing functions results in an approximately sparse linear system with storage memory requirements and a CPU time for computing the matrix coefficients proportional to the number of unknowns.

Analysis of electrically large concave scatterers with the integral equation mei
http://hdl.handle.net/2117/97886
Analysis of electrically large concave scatterers with the integral equation mei
Rius Casals, Juan Manuel; Carpintero, C Pérez; Cardama Aznar, Ángel; Michalski, Krzysztof
The integral equation MEI (IEMEI) is a new, sparse matrix formulation of the boundaryelement method, which is particularly well suited for large convex scatterers. In this Letter we explain why the original implementation of IEMEI fails for large concave objects and propose a remedy. © 1997 John Wiley & Sons, Inc. Microwave Opt Technol Lett 14:287–289, 1997.
Wed, 07 Dec 2016 15:36:46 GMT
http://hdl.handle.net/2117/97886
20161207T15:36:46Z
Rius Casals, Juan Manuel
Carpintero, C Pérez
Cardama Aznar, Ángel
Michalski, Krzysztof
The integral equation MEI (IEMEI) is a new, sparse matrix formulation of the boundaryelement method, which is particularly well suited for large convex scatterers. In this Letter we explain why the original implementation of IEMEI fails for large concave objects and propose a remedy. © 1997 John Wiley & Sons, Inc. Microwave Opt Technol Lett 14:287–289, 1997.

Impact of antenna errors on the radiometric accuracy of large aperture synthesis radiometers
http://hdl.handle.net/2117/97883
Impact of antenna errors on the radiometric accuracy of large aperture synthesis radiometers
Camps Carmona, Adriano José; Bará Temes, Francisco Javier; Torres Torres, Francisco; Corbella Sanahuja, Ignasi; Romeu Robert, Jordi
A classification of system errors in aperture synthesis radiometry applied to Earth observation is presented. A general procedure to quantify the impact of antenna errors on the radiometric accuracy is developed and is then particularized to an Lband Yshaped interferometer called MIRAS (microwave imaging radiometer by aperture synthesis) currently under study at the European Space Agency. This work analyzes in detail the impact of antenna errors on the radiometric accuracy of the instrument. These antenna errors are grouped into amplitude and phase antenna pattern errors, antenna position errors and antenna cross polarization errors. Special attention is paid to antenna coupling effects because of their importance in the selection of a suitable inversion algorithm for large aperture synthesis interferometers: the Gmatrix techniques or the Fourier techniques proposed for MIRAS.
Wed, 07 Dec 2016 15:22:34 GMT
http://hdl.handle.net/2117/97883
20161207T15:22:34Z
Camps Carmona, Adriano José
Bará Temes, Francisco Javier
Torres Torres, Francisco
Corbella Sanahuja, Ignasi
Romeu Robert, Jordi
A classification of system errors in aperture synthesis radiometry applied to Earth observation is presented. A general procedure to quantify the impact of antenna errors on the radiometric accuracy is developed and is then particularized to an Lband Yshaped interferometer called MIRAS (microwave imaging radiometer by aperture synthesis) currently under study at the European Space Agency. This work analyzes in detail the impact of antenna errors on the radiometric accuracy of the instrument. These antenna errors are grouped into amplitude and phase antenna pattern errors, antenna position errors and antenna cross polarization errors. Special attention is paid to antenna coupling effects because of their importance in the selection of a suitable inversion algorithm for large aperture synthesis interferometers: the Gmatrix techniques or the Fourier techniques proposed for MIRAS.

Fractal multiband antenna based on the sierpinski gasket
http://hdl.handle.net/2117/97877
Fractal multiband antenna based on the sierpinski gasket
Puente Baliarda, Carles; Romeu Robert, Jordi; Pous Andrés, Rafael; García, X; Benítez, F
Experimental and computed results show a multiband behaviour over five bands for the new fractal Sierpinski antenna. Such a behaviour is based on the selfsimilarity properties of the antenna's fractal shape, which might open an alternative way for designing new multiband and frequency independent antennas.
Wed, 07 Dec 2016 14:51:17 GMT
http://hdl.handle.net/2117/97877
20161207T14:51:17Z
Puente Baliarda, Carles
Romeu Robert, Jordi
Pous Andrés, Rafael
García, X
Benítez, F
Experimental and computed results show a multiband behaviour over five bands for the new fractal Sierpinski antenna. Such a behaviour is based on the selfsimilarity properties of the antenna's fractal shape, which might open an alternative way for designing new multiband and frequency independent antennas.

Perturbation of the sierpinski antenna to allocate the operating bands
http://hdl.handle.net/2117/97791
Perturbation of the sierpinski antenna to allocate the operating bands
Puente Baliarda, Carles; Romeu Robert, Jordi; Bartolomé, R; Pous Andrés, Rafael
A scheme for modifying the spacing between the bands of the Sierpinski antenna is introduced. Experimental results of two novel designs of fractal antennas suggest that the fractal structure can be perturbed to enable the logperiod to be changed while still maintaining the multiband behaviour of the antenna.
Mon, 05 Dec 2016 15:31:47 GMT
http://hdl.handle.net/2117/97791
20161205T15:31:47Z
Puente Baliarda, Carles
Romeu Robert, Jordi
Bartolomé, R
Pous Andrés, Rafael
A scheme for modifying the spacing between the bands of the Sierpinski antenna is introduced. Experimental results of two novel designs of fractal antennas suggest that the fractal structure can be perturbed to enable the logperiod to be changed while still maintaining the multiband behaviour of the antenna.

Multiband properties of a fractal tree antenna generated by electrochemical deposition
http://hdl.handle.net/2117/97785
Multiband properties of a fractal tree antenna generated by electrochemical deposition
Puente Baliarda, Carles; Claret Bonet, Josep; Romeu Robert, Jordi; LópezSalvans, M Q; Pous Andrés, Rafael
Experimental results on a fractal treelike antenna are reported. The fractal structure is generated by electrochemical deposition. The antenna presents a multiband behaviour with a denser band distribution than the previously reported Sierpinski fractal antenna. The matched frequencies are related to the length distribution over the fractal shape.
Mon, 05 Dec 2016 14:15:04 GMT
http://hdl.handle.net/2117/97785
20161205T14:15:04Z
Puente Baliarda, Carles
Claret Bonet, Josep
Romeu Robert, Jordi
LópezSalvans, M Q
Pous Andrés, Rafael
Experimental results on a fractal treelike antenna are reported. The fractal structure is generated by electrochemical deposition. The antenna presents a multiband behaviour with a denser band distribution than the previously reported Sierpinski fractal antenna. The matched frequencies are related to the length distribution over the fractal shape.

Integral formulation of the measured equation of invariance
http://hdl.handle.net/2117/97784
Integral formulation of the measured equation of invariance
Rius Casals, Juan Manuel
A novel integral formulation of the measured equation of invariance is derived from the reciprocity theorem. This formulation leads to a sparse matrix equation for the induced surface current, resulting in great CPU time and memory savings over the conventional approaches. The algorithm has been implemented for twodimensional perfectly conducting scatterers.
Mon, 05 Dec 2016 13:58:13 GMT
http://hdl.handle.net/2117/97784
20161205T13:58:13Z
Rius Casals, Juan Manuel
A novel integral formulation of the measured equation of invariance is derived from the reciprocity theorem. This formulation leads to a sparse matrix equation for the induced surface current, resulting in great CPU time and memory savings over the conventional approaches. The algorithm has been implemented for twodimensional perfectly conducting scatterers.

The theoretical error in the integral equation mei
http://hdl.handle.net/2117/97778
The theoretical error in the integral equation mei
Rius Casals, Juan Manuel; Carpintero, C Pérez; Cardama Aznar, Ángel; Mosig, J R
The theoretical, or nonnumerical error in the integral equation MEI (IEMEI) is analysed and compared to the numerical error in the method of moments (MoM). It is found that, although this error does not decrease with the discretisation step, it is smaller for the usual discretisation than the error in the MoM.
Mon, 05 Dec 2016 13:42:04 GMT
http://hdl.handle.net/2117/97778
20161205T13:42:04Z
Rius Casals, Juan Manuel
Carpintero, C Pérez
Cardama Aznar, Ángel
Mosig, J R
The theoretical, or nonnumerical error in the integral equation MEI (IEMEI) is analysed and compared to the numerical error in the method of moments (MoM). It is found that, although this error does not decrease with the discretisation step, it is smaller for the usual discretisation than the error in the MoM.

Frequency extrapolation in the integral equation mei
http://hdl.handle.net/2117/97776
Frequency extrapolation in the integral equation mei
Rius Casals, Juan Manuel; Carpintero, C Pérez; Cardama Aznar, Ángel; Mosig, J R
An algorithm to extrapolate in frequency the matrix coefficients of the IEMEI method is presented. This results in a total operation count to compute the induced current in electromagnetic scattering problems proportional to the number of unknowns, which in 2D is proportional to the working frequency.
Mon, 05 Dec 2016 13:32:15 GMT
http://hdl.handle.net/2117/97776
20161205T13:32:15Z
Rius Casals, Juan Manuel
Carpintero, C Pérez
Cardama Aznar, Ángel
Mosig, J R
An algorithm to extrapolate in frequency the matrix coefficients of the IEMEI method is presented. This results in a total operation count to compute the induced current in electromagnetic scattering problems proportional to the number of unknowns, which in 2D is proportional to the working frequency.